/*
 * Copyright 2017 Huawei Technologies Co., Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.servicecomb.springboot.starter.configuration;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.configuration.AbstractConfiguration;
import org.springframework.core.env.CompositePropertySource;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.EnumerablePropertySource;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.StandardEnvironment;

/**
 *
 */
public class ConfigurableEnvironmentConfiguration extends AbstractConfiguration {

  private final ConfigurableEnvironment environment;

  public ConfigurableEnvironmentConfiguration(ConfigurableEnvironment environment) {
    this.environment = environment;
  }

  @Override
  protected void addPropertyDirect(String key, Object value) {

  }

  @Override
  public boolean isEmpty() {
    return !getKeys().hasNext();
  }

  @Override
  public boolean containsKey(String key) {
    return this.environment.containsProperty(key);
  }

  @Override
  public Object getProperty(String key) {
    return this.environment.getProperty(key);
  }

  @Override
  public Iterator<String> getKeys() {
    List<String> result = new ArrayList<>();
    for (Map.Entry<String, PropertySource<?>> entry : getPropertySources().entrySet()) {
      PropertySource<?> source = entry.getValue();
      if (source instanceof EnumerablePropertySource) {
        EnumerablePropertySource<?> enumerable = (EnumerablePropertySource<?>) source;
        for (String name : enumerable.getPropertyNames()) {
          result.add(name);
        }
      }
    }
    return result.iterator();
  }

  private Map<String, PropertySource<?>> getPropertySources() {
    Map<String, PropertySource<?>> map = new LinkedHashMap<>();
    MutablePropertySources sources = (this.environment != null ? this.environment
        .getPropertySources() : new StandardEnvironment().getPropertySources());
    for (PropertySource<?> source : sources) {
      extract("", map, source);
    }
    return map;
  }

  private void extract(String root, Map<String, PropertySource<?>> map,
      PropertySource<?> source) {
    if (source instanceof CompositePropertySource) {
      for (PropertySource<?> nest : ((CompositePropertySource) source)
          .getPropertySources()) {
        extract(source.getName() + ":", map, nest);
      }
    } else {
      map.put(root + source.getName(), source);
    }
  }
}
